Factors influencing the outcome of magnetic sphincter augmentation for chronic gastroesophageal reflux disease

Magnetic sphincter augmentation (MSA) is a surgical treatment option for patients with gastroesophageal reflux disease (GERD). MSA consistently improves quality of life, maintains freedom from PPIs, and objectively controls GERD. However, up to 24% of patients did not achieve these outcomes. We sought to identify factors predicting outcomes after MSA placement with the aim of refining selection criteria. We retrospectively analyzed clinical, endoscopic, manometric, pH data, and intraoperative factors from two databases: Pivotal Trial (N = 99) and our prospectively maintained esophageal database (N = 71). A priori outcomes were defined as excellent (GERD-HRQL < 5, no PPI, no esophagitis), good (GERD-HRQL 6-15, no PPI, grade A esophagitis), fair (GERD-HRQL 16 to 25, PPI use, grade B esophagitis), and poor (GERD-HRQL > 25, PPI use, grade C/D esophagitis). Univariable and multivariable logistic regression analyses were performed to determine predictors of achieving an excellent/good outcome. A total of 170 patients underwent MSA with a median age of 53 years, [43-60] and a median BMI of 27 (IQR = 24-30). At baseline, 93.5% of patients experienced typical symptoms and 69% atypical symptoms. Median DeMeester score was 37.9 (IQR 27.9-51.2) with a structurally intact sphincter in 47%. Esophagitis occurred in 43%. At 48 [19-60] months after MSA, excellent outcomes were achieved in 47%, good in 28%, fair in 22%, and poor in 3%. Median DeMeester score was 15.6 (IQR = 5.8-26.6), esophagitis in 17.6% and daily PPI use in 17%. At univariable analysis, excellent/good outcomes were negatively impacted by BMI, preoperative LES residual pressure, Hill grade, and hiatal hernia. At multivariable analysis, BMI > 35 (OR = 0.05, 0.003-0.78, p = 0.03), structurally defective LES (OR = 0.37, 0.13-0.99, p = 0.05), and preoperative LES residual pressure (OR = 0.89, 0.80-0.98, p = 0.02) were independent negative predictors of excellent/good outcome. Magnetic sphincter augmentation results in excellent/good outcomes in most patients but a higher BMI, structurally defective sphincter, and elevated LES residual pressure may prevent this goal.